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The thymus regulates a specific microenvironment for the growth and maturation of naive T cells. Involution of immune function was an important factor during body aging. Preventing the senescence of immune organs has become a major medical issue. Resveratrol (RSV) has been proved to delay the aging of many organs including the thymus. However, the underlying mechanism remains indefinite and the dosages of RSV on thymus involution need to be further clarified. In the current study, the senescence-accelerated mice were produced using d-galactose for two months. RSV at different dosages (25, 50, 100 mg kg −1 day −1 ) was then administered. The alteration of the thymic morphological structure was observed. It showed that three dosages of RSV significantly decreased cellular senescence of the thymus and no dosage difference was detected. For cellular proliferation and apoptosis of the thymus, 50 and 25 mg/kg per day of RSV displayed the best effects on cellular proliferation and apoptosis in the thymus, respectively. Furthermore, 50 mg/kg per day of RSV increased the expression of FoxN1 both at transcription and translation levels. These findings indicated that RSV could delay thymus atrophy in a dosage-dependent pattern and FoxN1 might involve in the beneficial mechanism of RSV, which was of great significance for the enhancement of thymic health and organic immunity. Practical applicationsResveratrol has been proved to delay aging of many organs including of thymus. In the present study, we explored the dosage of resveratrol on thymus involution and the expression of transcription factors forkhead box protein N1 (FoxN1) in the senescenceaccelerated mice induced by D-galactose. The results indicated that resveratrol could delay thymus atrophy in a dosage-dependent pattern within a certain dose range, and higher RSV concentration may have drug toxicity, which suggests that the dosage of RSV requires attention, And FoxN1 might involve in the beneficial mechanism of resveratrol supplement, which was of great significance to explore the mechanism for the enhancement of thymus immunity. K E Y W O R D S d-galactose, FoxN1, resveratrol, thymus involution How to cite this article: Wei T-T, Feng Y-K, Cao J-H, et al. Dosage effects of resveratrol on thymus involution in D-galactose-treated mice.

Myocardial regeneration is identified as a concept at histological level. The core content is to increase the number of cardiomyocytes (CMs), so as to maintain the steady state of CMs under pathological or physiological conditions and ensure the normal cardiac function. In this review, we discussed the relevant factors involved in the regeneration of CMs, generalized in mice, large mammals and human. During different development stages of mammalian hearts, CMs showed several controlling and growth modes on the physiological or pathological state: mitosis, hypertrophy, nuclear polyploidy and multinucleation, amitosis and etc. We also discussed the mechanisms of specific microRNAs implicated in the cardiac development, as well as disease-induced apoptosis in CMs and the process of re-entering cell cycle after injury. It is hoped that this review will contribute to a deeper understanding of therapeutic approaches for myocardial regeneration after injury.

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